Armature arrangement



A. HUFNAGEL ARMATURE ARRANGEMENT 2 Sheets-Sheet 1 Filed Oct. 25, 1967 [NI Emma Pew flu/gage! f 41.4. ax

H/f JQ' Om/E'K kw 4 mm Aug. 12, 1969 A. HUFNAGEL ARMATURE ARRANGEMENT 2 Sheets-Sheet 2 Filed Oct. 25, 1967 Patented Aug. 12, 1969 3,461,411 ARMATURE ARRANGEMENT Andrew Hufnagel, Penn Hills Township, Allegheny County, Pa, assignor to Westinghouse Air Brake Company, Swissvale, Pa., a corporation of Pennsylvania Filed Oct. 25, 1967, Ser. No. 677,924 Int. Cl. HOlf 7/08 U.S. Cl. 335270 13 Claims ABSTRACT OF THE DISCLOSURE An improved armature arrangement having in combination with the armature an electromagnet which cooperates to move the armature Whenever the electromagnet is energized. The armature is comprised of a flattened elongated member, one end of which is a fulcrum end having a beveled surface. The armature is disposed adjacent the electromagnet and interposed between the armature and the electromagnet is a flat, plate-like hinge spring secured at one end thereof to the elongated armature. A hinge block is secured to the electromagnet and is physically disposed to secure the other end of the hinge spring to the electromagnet. The hinge block has a portion thereof extending beneath the fulcrum end of the armature. A Spring is disposed between the hinge block extending portion and the fulcrum end of the armature to force the fulcrum end in the direction of the flat hinge spring.

This invention relates to an improved armature arrange ment.

More specifically, this invention relates to an improved armature arrangement having in combination with the armature an electromagnet which cooperates to move the armature whenever the electromagnet is energized. The armature is comprised of a flattened elongated member, one end of which is a fulcrum end having a beveled surface. The armature is disposed adjacent the electromagnet and interposed between the armature and the electromagnet is a flat, plate-like spring secured at one end thereof to the elongated armature. A hinge block is secured to the electromagnet and is physically disposed to secure the other end of the hinge spring to the electromagnet. The hinge block has a portion thereof extending beneath the fulcrum end of the armature. A spring is disposed between the hinge block extending portion and the fulcrum end of the armature to force the fulcrum end in the direction of the flat hinge spring.

Today as never before in the field of vital relays there has been an intensive effort to reduce the cost of manufacturing these relays. The spiraling increase in all costs has driven the technology to the limits of capacity in the area of new materials to do old jobs. New levels of ingenuity coupled with experience have been called upon to meet the needs of industry in reducing the total number of manual adjustments and components that where in the past employed in the manufacture of precision vital relays. The invention to be described hereafter presents a new armature arrangement which provides with pleasing simplicity a vital relay that meets all the demanding requirements of the market place while reducing the number of components and operational steps required in manufacturing the relay.

It is therefore an object of this invention to provide an improved vitual relay armature arrangement which equals or exceeds the standards of quality and performance set by industry and does so with fewer components and operational steps in manufacture.

Another object of this invention is to provide an improved armature arrangement that can withstand sudden shock loading without distortion to spring elements due to the incorporation of a safety stop ledge that limits the total possible physical excursion of the armature and related springs while simultaneously allowing normal armature movement during conventional operation.

Another object of this invention is the provision of a novel armature structure which allows precise adjustment with a minimal number of steps in production while retalining a high level of dimensional accuracy in the finished re ay.

Yet another object of this invention is the provision of a novel manner of insuring an air gap to allow the armature to remain in magnetic balance with an associated electromagnet.

A final object is the incorporation of a unique hinge spring which improves lateral armature stability with reference to the electromagnet.

In the attainment of the foregoing objects the improved armature arrangement includes in combination with an armature an electromagnet which cooperates to move the armature whenever a DC. signal causes the electromagnet to be energized. Basically, the armature takes the form of a flattened elongated member, one end of which is a fulcrum end, the fulcrum end having a beveled surface thereat. The beveled portion provides a fulcrum edge, about which edge the armature pivots whenever the electromagnet is energized. The armature is disposed adjacent the electromagnet and there is interposed between the elongated armature member and the electromagnet a flat, plate-like nonmagnetic hinge spring secured at one end thereof to the elongated armature member.

A hinge block is secured to the electromagnet and physically disposed to secure the other end of the hinge spring to the electromagnet. The hinge block has a portion thereof which extends beneath the fulcrum end of the armature. A helical compression spring is disposed between the extending portion of the hinge block and the fulcrum end of the armature to force the fulcrum edge in the direction of the hinge spring. The hinge spring is substantially the same width as the armature to provide the armature with lateral stability with reference to the electromagnet.

The armature has a nonmagnetic stop pin thereon positioned toward the end of the armature remote from the fulcrum end and directed toward the electromagnet. There is also provided as part of the arrangement a first and second nonmagnetic spacer element. The first spacer element is secured to the hinge spring at the end of the hinge spring where the hinge spring is secured to the armature and the first spacer element is disposed between the hinge spring and the electromagnet.

The second spacer element is interposed between the hinge spring and the hinge block, the combined thicknesses of the hinge spring and the second spacer element equaling the height of the stop pin to thereby provide a parallel nonmagnetic gap between the armature and the electromagnet whenever the electromagnet is energized The nonmagnetic gap is a well-known expedient in devices of this nature for the purpose of ensuring that when the electromagnet is deenergized the armature will properly drop away from it in spite of any residual magnetism that may remain in the core structure and armature. Any change in either gap will cause an undesirable change in the calibration of the relay, and in a vital relay a decrease in either gap is a particular hazard since it tends to prevent the armature from dropping away properly.

The first spacer and the hinge spring have a combined thickness dimension somewhat less than the height of the stop pin to thereby provide a safety function in the event that the stop pin experiences excessive wear or damage over a period of time.

It should also be noted that the second spacer extends along the hinge spring to a point where the fulcrum edgeengages the side of the second spacer element facing the fulcrum edge to thereby establish a pivotal action about the fulcrum edge which allows the hinge spring to flex in a gradual and uniform manner.

Other objects and advantages of the present invention will become apparent from the ensuing description of illustrative embodiments thereof, in the course of which reference is had to the accompanying drawings in which:

FIG. 1 depicts a DC. vital relay which embodies the invention.

FIG. 2 illustrates an armature arrangement which embodies the invention and illustrates the function of the invention in operation.

FIG. 3 sets forth a prior art armature arrangement.

FIG. 4 shows in part some of the major components of an armature arrangement which embodies the invention.

A description of the above embodiment will follow and then the novel features of the invention will be presented in the appended claims.

Reference is now made to FIG. 1 in which there is illustrated a portion of a DC. neutral relay embodying the invention. Basically, this relay functions in a similar manner to the relay shown and described in great detail in Letters Patent of the United States No. 2,833,885, granted to Wesley B. Wells and Harry E. Ashworth, on May 6, 1958, for Electrical Relays. Basically, the DC. neutral relay has a coil 11 which has passing therethrough a core member 12. This coil 11 is electrically connected to coil terminal fingers 19. Coil terminal fingers 19 and their electrical connections are not shown but it is to be understood that when this plug-in type relay is pressed into position and the coil terminal fingers 19 engage a terminal socket, the DC. power supply will be connected to the coil 11 and accordingly produce a magnetic field within the core 12. The coil 11 and core 12 are mounted upon a relay frame 13 made of a nonmagnetic material, and the core 12 is secured by bolts 14 and 16 to the relay frame 13. In order that this relay be readily removed from the plugged-in position and reinserted there is provided a handle 17, which handle 17 is secured by screws 18 to the relay frame 13.

In addition, there is provided in this type of relay a permanent magnet structure 26, here shown as a single element, and this permanent magnet, the function of which will be described hereafter, is secured to the frame 13 by bolts 27.

Within the frame 13 and shown in dotted outline are a pole piece 28 and a pole piece 29. Each of these pole pieces respectively has a pole piece extension 31 and a pole piece extension 32. The under surface of the pole piece extension 32 has a pole face 34, and the pole piece extension 31 has a pole face 33. Immediately beneath the pole faces there is an armature structure 36. This armature 36 will be explained in more detail when FIG. 2 is described. The armature 36 has at its left-hand portion a fulcrum point 37. This fulcrum point 37 has been formed by the beveling of a surface on the left-hand end of the armature 36. The beveled surface 33, as itmeets with the upper surface of the armature, provides the fulcrum point 37 about which this armature will pivot.

Also secured to the frame 13 is a hinge block 39, which hinge block 39 has a depending ledge portion 40 which extends underneath the end of the armature 36. The function of this ledge portion will be explained hereafter. The hinge block 39 is secured to the frame by bolts 41, and there is an extending portion 45 of the hinge block 39 which also extends underneath the end of the armature 36. There is provided a helical compression spring 42 between the armature 36 and the hinge block extending portion 45. This helical spring 42 is maintained in position by a spring retaining opening 43 in the armature 36 and by a spring retaining opening 44 in the hinge block extending portion 45. This helical compression spring directs substantially all of its force through the fulcrum point 37 of the armature 36 and forces the armature toward the coil and core structure 1112 which form an electromagnetic means.

The armature 36 has interposed between its fulcrum point 37 and the pole face 34 of the pole piece extension portion 32 a spacer 51 as well as a flat, plate-like hinge spring 52. The flat, plate-like hinge spring 52 is secured at one end to the armature 36 by screws 53. Between screws 53 and the hinge spring 52 is a spacer 54. The hinge block 39 also has interposed between the pole face 34 and the hinge block 39, the spacer 51 as well as the hinge spring 52. The functional cooperation of the spacers 51 and 54 and the cooperation with the hinge spring 52 and the armature 36 with its fulcrum point 37 will be discussed in detail when FIG. 2 and its functional operation are set forth in detail hereafter.

The armature 36 also has near its right-hand end an armature stop pin 56, the function of which will be explained hereafter. Secured on the bottom side of the armature 36 is a contact driver bracket 57, which bracket 57 is secured by screws 58 to the bottom of the armature 36. There is connected to the bracket 57 a contact driver of insulating material 59, which contact driver moves in unison with the armature 36 whenever the relay coil and core have been energized in a manner to be described hereafter. Secured to the frame 13, by means not shown, is an insulating contact block 61. Passing through the insulating contact block 61 is a rigid front contact portion 62. It should be noted at this time that the operation and advantages of the contact structure to be described hereafter will be set forth in my copending application, Ser. No. 677,928, filed Oct. 25, 1967, for Fail- Safe Vital Relay Contact Arrangement, and only a brief structural description of this section of the relay will be made in this application. Accordingly, the rigid front contact portion 62 has sandwiched therein a front contact spring which has an extending front contact spring portion 63 which terminates in a silver impregnated carbon front contact tip 64. While not shown in this figure, it will be understood that the front contact spring 63 is electrically integral with a front contact terminal finger 66 shown to the left of the contact block 61.

There is also depicted here a heel contact terminal finger 67, as well as a back contact terminal finger 74, each of which is respectively electrically connected to a heel contact and a back contact to now be described. The heel contact has a rigid portion 69 through which passes the heel contact member 68. This heel contact member 68 has a machined slot 71 in a surface thereof adjacent the rigid portion 69. The function of this slot is explained in detail in the copending application noted above. Near the end of the heel contact member 68 is a heel contact tip 73 and the heel contact member 68 is secured to the contact driver 59 by a bendable clip 72. The back contact terminal finger 74 passes through the block 61 and is electrically secured to the back contact spring portion 76, which spring is secured within the rigid back contact portion 77. The spring 76 terminates with a back contact tip 78.

The entire mechanism just described is housed within a housing 48 here only partially shown. It is to be understood that the housing 48 completely surrounds the armature and contact mechanism to maintain the relay free from dust and contamination. The housing 48 is a transparent plastic cover and is secured to the frame 13 by screws 49.

The relay shown here is in its rest condition. By this it is meant to convey the concept that when the relay is in its deenergized position the armature 36 is at rest upon a portion of the permanent magnet 26, as is illus trated herein FIG. 1. The magnetic field created by the permanent magnet is depicted by the dashed line 21 which shows the permanent magnetic field passing upwardly through the pole piece 28 through the core 12 of the electromagnetic means, down through the pole piece 29,

through a portion of the pole piece extension 32, and down through the hinge spring 52 and the fulcrum point area 37, into the armature 36, along the armature 36, and back into what is designated as a south pole of the permanent magnet 26. The designations S and N shown in this figure on the permanent magnet 26 are present for purposes of illustration to indicate the polarity of the magnet 26.

When the relay has been plugged in and direct current is flowing in coil 11, the electromagnetic field thereby created in core 12 will take on the direction shown by the solid line 22 which contains arrows depicting the relative direction of the electromagnetic field. It will be appreciated that as the electromagnetic field increases in strength, the magnetic lines of force, namely, the electromagnetic field as shown by the arrows 22 and the permanent magnetic field shown by the arrows 21, will oppose each other. When the electromagnetic field exceeds the permanent magnetic field, the path of the electromagnetic field will be downwardly from the core 12 through the pole piece 28, through a portion of the pole piece extension 31, into armature 36, along the armature 36, upward to the fulcrum point area 37, and into the pole piece extension 32 and pole piece 29, and finally back into the core 12. Of course, when the coil 11 is deenergized, the electromagnetic field collapses and the permanent magnetic field, shown by the dotted lines 21, becomes of a strength sufficient to pull the armature 36 back into its rest position on the permanent magnet 26, as is depicted here.

Reference is now made to FIG. 2 in which the armature, which forms the subject of the invention here being described, is shown in two different positions. The chain line position depicts the armature 36 in a highly exaggerated aspect of its movement. This has been done in order to facilitate the understanding of the physical cooperation of the armature 36 with the spacer 51 and the hinge spring 52. In this figure, reference numerals that are compatible with the description made of FIG. 1 are used throughout in describing the functional operation of the armature 36.

As has been noted, when the armature is moving between its extreme positions, it must move freely about a pivot point, it must pivot in a reliable fashion with a minimum number of parts, coupled with the minimum number of adjustments needed to install the armature within the relay, and maintain the adjustments over long periods of use. It can be seen from this illustration that the armature, which pivots about the fulcrum point 37, has the helical compression spring 42 so disposed that the line of force of the helical compression spring 42 is directed through the fulcrum point of the armature, which fulcrum point 37 is in intimate contact with the spacer 51. This arrangement of the spacer 51 and the hinge spring 52 affords a rolling, flexing type action of the hinge spring 52 as it cooperates with the spacer 51. The hinge spring 52 simultaneously experiences a gradual even flexure over its entire length due to the positioning of the spacer 51. This spacer 51 forms an important function in that it provides, because of its thickness dimension coupled with the dimension of the hinge spring 52, a constant nonmagnetic gap between the end of the armature containing the beveled portion 38 and the pole face 34 of pole piece eX- tension 32. In other words, whenever the armature comes to rest against the pole face 33, as when an electromagnetic field is applied, the stop pin 56 comes to bear upon the pole face 33 of the pole piece extension 31. At this point the overall thickness dimensions of the combined spacer 51 and the hinge spring 52 are the same as the dimension of the stop pin 56. This provides a balanced magnetic flux path between the pole piece extensions 32 and 33. Therefore, when the armature is in its actuated condition, the armature is positioned with an equal spacing between either end of the armature. This provides a highly desirable stable condition in which the armature may experience millions of excursions while maintaining this very important balance dimension between the armature and the magnetic pole pieces here involved.

Accordingly, the armature 36 possesses a novel physical arrangement in which there is employed the fixed thickness shim or spacer 51 with a horizontal hinge spring 52 to provide a dependable fixed air gap at the rear of the armature with no need for subsequent adjusting because the shim or spacer 51, as well as the horizontal hinge spring 52, provides in one manufacturing operation a guaranteed fixed distance between armature 36 and pole face 34.

Another novel aspect of this armature is the provision of another spacer 54 located at the front or right-hand portion of the hinge spring 52. This spacer 54 provides, because of its thickness coupled with the thickness of the hinge spring 52, an overall connection which will function as a safety stop which will be better appreciated when a study of FIG. 4 is made hereafter. Basically, the thickness of spacer 54 in combination with the thickness of the hinge spring 52 provides a dimension which is less than the overall dimension of the stop pin 56. The stop pin 56 after repeated use may become worn or damaged, .and in this case the upward excursion of the .armature 36 will be limited due to the presence of the spacer 54 which comes into contact with the pole face 33 of pole piece extension 31. This novel safety feature does away with the need for additional safety stops currently found in the prior art.

FIG. 3 depicts an armature arrangement containing many of the features in the prior art over which this invention reflects an improvement.

Refer now to FIG. 3 which sets forth a prior art configuration used with considerable success in the past. As with many of the prior art devices this relay armature presented a physical environment in which the effort to attain initial adjustments of the parts, as well as future adjustments which arose as the relay experienced extended use, established the need for the new and improved armature here described. In the prior art armature arrangement shown in FIG. 3 there is depicted an armature which has a stop pin 91 at the right-hand end thereof. Safety stop pins 92 and 93 are shown to the left of the stop pin 91. The dimensional relationships of these stop pins will be discussed hereafter. In order to secure the armature for pivotal movement there were employed three spring elements, two horizontal springs 83 and 84 which were secured by bolts 88 and 89 to a relay frame portion not shown in this figure. A vertical spring 85 was also secured to the frame of the relay, which frame of course is not shown here. The vertical spring was secured to the frame by bolts 86 and the upper end of the vertical spring 85 was secured by bolts 87 to the armature. The right-hand ends of the horizontal springs 83 and 84 were spaced away from the armature 80 by the spacer 82 and secured to it by screws 94. This is shown graphically in the cut-away section 81 of the armature 80.

Reference will now be made to FIG. 4 which shows the improved spring arrangement of this invention in three-dimensional detail. The horizontal hinge spring 52 is depicted as well as the spacer 51 and the spacer 54, which spacer 54 is secured to the armature 36 by the screws 53 in a manner previously described. At the righthand end of the armature is the stop pin 56. Note here the dimensional relationship of the stop pin 56. For example, this stop pin might have a dimension of 0.23 inch, which of course, in order to provide a balanced magnetic flux path, would require the dimensions of spacer 51 and spring 52 to also be -023 inch. This is accomplished by the utilization of a spacer 51 which has a thickness of 0.17 inch in combination with a hinge spring which has a thickness of .006. The added thicknesses of these two elements, namely, the spacer 51 and the hinge spring 52, provides a total thickness of .023 inch which is the same as for the stop pin 56. It can be seen here that there is therefore provided a guaranteed balanced magnetic flux path betwen either end of the armature which is highly desirable in vital relays of this type. In the event that the stop pin 56 should wear in any manner, the thickness of the spacer 54 positioned at the right-hand end of the hinge spring 52 will afford a safety factor because the thickness of the spacer 54 has been selected at 0.12 inch which, of course, when added to the .006 inch thickness of the hinge spring 52 provides an overall thickness of .018 inch which allows for .a margin of safety by the elementary inclusion of the simple shim in the final construction of this armature arrangement.

Referring back to FIG. 3, the safety stop pins 92 and 93 had to have a dimension carefully machined to 0.18 inch in order that the required safety margin be maintained with reference to the safety stop pin 91 which was selected to be .023 inch.

When FIGS. 3 and 4 are studied together, one can see that but a single hinge spring 52 is required, which when secured to the frame provides an extremely rigid member from the standpoint of any lateral motion which might be impressed upon the armature arrangement, which lateral motion is depicted by arrow 70, in FIG. 4. Note, in other arrangements where several hinge springs are used, such as 83 and 84 shown in FIG. 3, the possibility of lateral movement of the type just referred to is greatly increased because of the smaller dimensions and lower rigidity to this type of spring arrangement. The fact that more fasteners are required in the form of bolts, for example 88 and 89, created the possibility of repeated adjustments becoming necessary over the life of the relay.

The vertical hinge spring 85, while providing a flexible arrangement at the rear of the armature, is also susceptible of the need for adjustments over the life of the relay. The compression spring 42 of the new armature arrangement, which has been shown again in FIG. 4, is a simple compression spring configuration which, because of its positioning within the retaining openings 43 and 44 best seen in FIG. 2, allows for the complete abandonment of concern over adjustments of this spring during the life of the relay, for once the spring 42 has been placed within its retaining openings 43 and 44, as shown in FIG. 2, it may be left in that position for the life of the relay.

In FIG. 2 an additional safety feature is clearly shown in that the hinge block 39 has a safety stop ledge 40 which prevents the armature 36 from traveling downwardly beyond this ledge should the relay receive a sudden physical shock. This safety stop ledge feature therefore ensures that the hinge spring 52 will never experience a flexure which would cause a permanent deformation of the hinge spring.

In the prior art relays, while not shown, once the relay had been put together, dowels in the form of rods had to be inserted through the critical elements, namely, the springs and the blocks that the springs were attached to, which blocks, not shown here, were secured to the frame.

From the above description it is now readily evident that there has been provided an improved armature arrangement which requires the minimum of adjustments while providing the maximum in safety from the standpoint of loss of adjustment over a period of time coupled with a reduction in the total number of parts which results in an enhanced relay armature, whose overall manufacturing costs and functional qualities meet the highest tests of the industry.

While there has been described What is at present considered to be the preferred embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Having thus described my invention, what I claim is:

1. An improved relay armature arrangement having in combination with said armature and electromagnetic means which cooperates to move said armature whenever said electromagnetic means is energized,

, (a) saidarmature being comprised of a flattened elongated member, one end of which is a fulcrum end,

said armature disposed adjacent said electromagnetic means and having interposed between said elongated armature member and said electromagnetic means a flat plate-like nonmagnetic hinge spring member secured at one end thereof to said elongated armature member, I

(b) a hinge block means secured to said electromagnetic means and physically disposed to secure the other end of said hinge spring to said electromagnetic means,

said hinge block having a portion thereof extending beneath said fulcrum end of said armature,

(c) biasing means disposed" between said hinge block extending portion and said fulcrum end of said armature to force said fulcrum end in the direction of said fiat hinge spring.

2. The improved relay of claim 1 wherein said armature member is a rectangular plate having a beveled surface at said fulcrum end of said armature member, which beveled portion provides an edge which is biased toward said hinge spring and about which edge said armature pivots whenever said electromagnetic means is energized.

3. The improved relay of claim 2 wherein said biasing means is so positioned to direct all of its force directly toward said fulcrum edge.

4. The improved relay of claim 1 wherein said hinge block includes a safety stop ledge which extends beneath said fulcrum end of said armature to thereby limit the total possible, physical excursion of said armature while simultaneously allowing normal armature movement during conventional operation.

5. The improved relay of claim 4 wherein said armature has a stop pin thereon positioned toward the end of said armature remote from said fulcrum end pointing in the direction of said electromagnetic means,

said armature arrangement including a first and a second spacer element,

said first spacer element secured to said hinge spring at said one end of said hinge spring and disposed between said hinge spring and said electromagnetic means, said second spacer element interposed between said hinge spring and said hinge block, the combined thicknesses of said hinge spring and said second spacer element equaling the height of said stop pin to thereby provide a parallel gap between said armature and said electromagnetic means whenever said electromagnetic means is energized, said parallel gap providing a magnetically balanced armature and electromagnetic means arrangement,

said first spacer and said hinge spring having a combined thickness dimension somewhat less than the height of said stop pin to thereby provide a safety function in the "event that said stop pin experiences excessive wear over a period of time.

6. The improved relay of claim 5 wherein said second spacer extends along said hinge spring to a point where said fulcrum edge engages the side of said spacer element facing said fulcrum edge to thereby establish a pivotal action about said fulcrum edge which allows said hinge spring to flex in a gradual and uniform manner.

7. The improved relay of claim 6 wherein said fiat hinge spring is substantially the same width as said armature.

8. The improved relay of claim 7 wherein said biasing means is a helical compression spring which is con strained from lateral movement at either end by restraining means present in said armature and said hinge block.

9. An improved relay armature arrangement having in combination with said armature an electromagnetic means which cooperates to move said armature whenever said electromagnetic means is energized,

(a) said armature comprised of a flattened elongated member one end of which is a fulcrum end,

said fulcrum end having a beveled surface thereat, said beveled portion providing a fulcrum edge about which edge said armature pivots whenever said electromagnetic means is energized,

(b) said armature disposed adjacent said electromagnetic means and having interposed between said elongated armature member and said electromagnetic means a flat plate-like hinge spring member secured at one end thereof to said elongated armature memher,

() a hinge block means secured to said electromagnetic means and physically disposed to secure the other end of said hinge spring to said electromagnetic means, I

said hinge block having a portion thereof extending beneath said fulcrum end of said armature,

(d) biasing means disposed between said hinge block extending portion and said fulcrum end of said armature to force said fulcrum edge in the direction of said flat hinge spring,

(e) said armature having a stop pin thereon positioned toward the end of. said armature remote from said fulcrum end and pointing in the direction of said electromagnetic means,

(f) said armature arrangement including a first and second spacer element,

said first spacer element secured to said hinge spring at said one end of said hinge spring and disposed between said hinge spring and said electromagnetic means,

said second spacer element interposed between said hinge spring and said hinge block, the combined thicknesses of said hinge spring and said second spacer element equaling the height of said stop pin to thereby provide a parallel gap between said armature and said electromagnetic means whenever said electromagnetic means is energized, said parallel gap providing a magnetically balanced armature and electromagnetic means arrangement,

said first spacer and said hinge spring having a combined thickness dimension somewhat less than the height of said stop pin to thereby provide a safety function in the event that said step pin experiences excessive wear over a period of time.

10. The improved relay of claim 9 wherein said second spacer extends along said hinge spring to a point where said fulcrum edge engages the side of said spacer element forcing said fulcrum edge to thereby establish a pivotal action about said fulcrum edge which allows said hinge spring to flex in a gradual and uniform manner.

11. The improved relay of claim 10 wherein said flat hinge spring is substantially the same width as said armature to thereby provide lateral stability of said armature with reference to said electromagnetic means.

12. The improved relay of claim 11 wherein said biasing means is a helical compression spring which is constrained from lateral movement at either end by restraining means present in said armature and said hinge block.

13. The improved relay of claim 9 wherein said hinge block includes a safety stop ledge which extends beneath said fulcrum end of said armature to thereby limit the total possible physical excursion of said armature while simultaneously allowing normal armature movement during conventional operation.

References Cited UNITED STATES PATENTS 3,061,765 10/1962 Hess 335276 3,259,8l2 7/1966 ONeil 335-270 XR G. HARRlS, Primary Examiner US. Cl. X.R. 335276 

